Active cooling assembly for sensor module

ABSTRACT

An actively cooled nitrous oxide sensor module is provided. The actively cooled nitrous oxide sensor module includes a sensor unit comprising at least one of the nitrous oxide sensor and at least a portion of circuitry associated with the at least one nitrous oxide sensor. The actively cooled nitrous oxide sensor module also includes an active cooling assembly thermally coupled to the sensor unit. The active cooling assembly includes a coolant inlet and a coolant outlet. The active cooling assembly also includes a coolant path disposed between the coolant inlet and the coolant outlet. The active cooling assembly is configured to control a temperature of the sensor unit based, at least in part, on a circulation of a coolant flow therethrough.

TECHNICAL FIELD

The present disclosure relates to a cooling system, and more specifically to an active cooling assembly for a sensor unit of an engine system.

BACKGROUND

Engine systems may include a plurality of sensors, for example, sensors for measuring a quantity of Nitrous Oxides (NOx) present in an exhaust gas generated by the engine system. Such sensors may be located at various locations, such as, on or within an aftertreatment system associated with the engine system. These locations may experience elevated temperatures during operation of the engine system and/or the aftertreatment system. The elevated temperatures at such locations may result in an increase in temperature of the sensors placed therein. In a situation when the temperature of the sensors may exceed an operating temperature limit, the sensors may provide incorrect readings and/or may fail prematurely before an estimated life span, thereby causing an increase in service intervals and operating costs, and also affect an overall productivity of the system. This situation is especially prevalent among NOx sensors, which due to the nature of their operation are typically placed in direct exposure to the hot exhaust gases.

U.S. Pat. No. 8,341,949 describes an aftertreatment module. The aftertreatment module includes a housing having an exhaust inlet and an exhaust outlet. The aftertreatment module includes at least one NOx sensor disposed within the housing. The aftertreatment module also includes a thermal isolating structure connected directly to the housing. The thermal isolating structure includes a mounting plate disposed at a distance from the housing such that an air gap is formed between the mounting plate and the housing.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, an actively cooled nitrous oxide sensor module is provided. The actively cooled nitrous oxide sensor module includes a sensor unit comprising at least one nitrous oxide sensor and at least a portion of circuitry associated with the at least one nitrous oxide sensor. The actively cooled nitrous oxide sensor module also includes an active cooling assembly thermally coupled to the sensor unit. The active cooling assembly includes a coolant inlet and a coolant outlet. The active cooling assembly also includes a coolant path disposed between the coolant inlet and the coolant outlet. The active cooling assembly is configured to control a temperature of the sensor unit based, at least in part, on a circulation of a coolant flow therethrough.

In another aspect of the present disclosure, an engine system is provided. The engine system includes an engine having an exhaust conduit. The engine system includes a reductant injector coupled to the exhaust conduit. The engine system also includes a selective catalytic reduction module in fluid communication with the reductant injector. The selective catalytic reduction module is positioned downstream of the reductant injector with respect to an exhaust gas flow. The engine system further includes an actively cooled nitrous oxide sensor module. The actively cooled nitrous oxide sensor module includes a sensor unit provided in association with the selective catalytic reduction module. The sensor unit includes at least one nitrous oxide sensor and at least a portion of circuitry associated with the at least one nitrous oxide sensor. The actively cooled nitrous oxide sensor module also includes an active cooling assembly thermally coupled to the sensor unit. The active cooling assembly includes a coolant inlet and a coolant outlet. The active cooling assembly also includes a coolant path disposed between the coolant inlet and the coolant outlet. The active cooling assembly is configured to control a temperature of the sensor unit based, at least in part, on a circulation of a coolant flow therethrough.

In yet another aspect of the present disclosure, a method for cooling a nitrous oxide sensor is provided. The method includes providing an active cooling assembly in association with a sensor unit for the nitrous oxide sensor. The method includes receiving a coolant flow into a coolant inlet of the active cooling assembly from an aftercooler. The method also includes circulating the coolant flow through a coolant path of the active cooling assembly. The method further includes controlling a temperature of the sensor unit based, at least in part, on the circulation of the coolant flow therethrough.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross sectional view of an exemplary machine, according to an embodiment of the present disclosure;

FIG. 2 is a top right perspective view of an aftertreatment system showing an exemplary inlet sensor unit, according to an embodiment of the present disclosure;

FIG. 3 is a top left partial perspective view of the aftertreatment system showing an exemplary outlet sensor unit, according to an embodiment of the present disclosure;

FIG. 4 is a perspective view of the exemplary inlet sensor unit, according to an embodiment of the present disclosure; and

FIG. 5 is flowchart of a method of working of an active cooling assembly for the inlet and/or outlet sensor unit, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Referring to FIG. 1, a partial cross sectional view of a machine 100 is illustrated. More specifically, in the illustrated embodiment, the machine 100 is a locomotive. In other embodiments, the machine 100 may be associated with an industry including, but not limited to, transportation, construction, agriculture, forestry, material handling, and waste management. Accordingly, the machine 100 may be any machine such as, a mining truck, an off-highway truck, a wheel loader, a track loader, a track type tractor, and other such machines.

The machine 100 includes a frame 102. The frame 102 is configured to support one or more components of the machine 100. The machine 100 includes an operator cabin 104 provided on the frame 102. The operator cabin 104 may include an operator interface (not shown). The machine 100 includes a set of wheels 106 rotatably coupled to the frame 102. The set of wheels 106 are configured to provide mobility to the machine 100 on a set of rails (not shown).

The machine 100 includes an enclosure 108 provided on the frame 102. An engine system 110 is provided within the enclosure 108. The engine system 110 includes an engine 112. The engine 112 is an internal combustion engine powered by a fuel, such as, gasoline, diesel, natural gas, and any other fuel known in the art. The engine 112 is configured to provide power to the machine 100 for mobility and other operational requirements.

The engine system 110 includes a turbocharger 114. The turbocharger 114 is fluidly coupled to an intake manifold 116 and an exhaust manifold (not shown) of the engine 112. The turbocharger 114 is configured to compress intake air before being supplied to the intake manifold 116 of the engine 112. The engine system 110 also includes an aftercooler 118. In other embodiments, the engine system 110 may include an intercooler. The aftercooler 118 is fluidly coupled to the turbocharger 114 and the intake manifold 116 and is provided downstream of the turbocharger 114 with respect to a flow of the intake air. The aftercooler 118 is configured to cool the compressed intake air supply of the compressed air to the intake manifold 116. The aftercooler 118 also includes an aftercooler cooling circuit (not shown). The aftercooler cooling circuit is configured to allow heat exchange with the aftercooler 118.

The machine 100 includes an aftertreatment system 120. Referring to FIG. 2, a top right perspective view of the aftertreatment system 120 is illustrated. The aftertreatment system 120 is configured to reduce the amount of regulated exhaust constituents in the exhaust gas flow from the engine 112. The aftertreatment system 120 includes an inlet 202. The inlet 202 is provided in fluid communication with the exhaust manifold of the engine 112. The inlet 202 is configured to receive the exhaust gas flow within the aftertreatment system 120. The aftertreatment system 120 includes a casing 204. The casing 204 is configured to enclose and support one or more components of the aftertreatment system 120.

The aftertreatment system 120 may include one or more Selective Catalytic Reduction (SCR) modules (not shown) and/or a reductant injector (not shown) configured to introduce a reductant into the exhaust gas flow. The reductant injector may be coupled to an exhaust conduit (not shown) of the engine 112 and provided in fluid communication with the SCR modules. Further, the SCR modules may be provided downstream of the reductant injector with respect to the exhaust gas flow. The reductant, and/or decomposition byproducts thereof, disposed on the SCR modules may react with Nitrous Oxides (NOx) present in the exhaust gas flow to form water (H₂O) and diatomic nitrogen (N₂). Specifically, the reductant may be gaseous or liquid urea, ammonia, any of a variety of hydrocarbons, or other similar compositions as known to one of ordinary skill in the art. Additionally or optionally, the aftertreatment system 120 may also include other components (not shown), such as, a Diesel Particulate Filter (DPF), a Diesel Emission Fluid (DEF), a Diesel Oxidation Catalyst (DOC), and so on.

The aftertreatment system 120 also includes an outlet 206. The outlet 206 is provided in fluid communication with the casing 204. The outlet 206 is configured to exit the exhaust gas flow from the aftertreatment system 120. The aftertreatment system 120 includes a sensor unit placed at the inlet 202 of the aftertreatment system 120, hereinafter referred to as an inlet sensor unit 208, or the exhaust conduit of the engine 112.

The inlet sensor unit 208 includes a body 210 configured to enclose at least one of an inlet Nitrous Oxide (NOx) sensor 214 and at least a portion of an inlet sensor circuitry 216 associated with the inlet NOx sensor 214. The inlet sensor circuitry 216 may include, but not limited to, communication cables, a controller, a Printed Circuit Board (PCB), other electrical/electronic components, and so on. The inlet NOx sensor 214 is configured to generate a signal indicative of an amount of NOx present in the exhaust gas flow entering the aftertreatment system 120 at the inlet 202. Further, the inlet sensor unit 208 includes an active cooling assembly 212. The active cooling assembly 212 will be explained in more detail with reference to FIG. 4.

Referring to FIG. 3, a top left partial perspective view of the aftertreatment system 120 is illustrated. As shown in FIG. 3, the aftertreatment system 120 also includes an outlet sensor unit 302 placed at the outlet 206 of the aftertreatment system 120 or the exhaust conduit of the engine 112.

The outlet sensor unit 302 includes a body 304 configured to enclose at least one of an outlet Nitrous Oxide (NOx) sensor 314 and at least a portion of an outlet sensor circuitry 316 associated with the outlet NOx sensor 314. The outlet sensor circuitry 316 may include, but not limited to, communication cables, a controller, a Printed Circuit Board (PCB), other electrical/electronic components, and so on. The outlet NOx sensor 314 is configured to generate a signal indicative of an amount of NOx present in the exhaust gas flow exiting the aftertreatment system 120 from the outlet 206. Additionally, the outlet sensor unit 302 includes an active cooling assembly 312 that is substantially similar to the active cooling assembly 212. The active cooling assemblies 212, 312 will be explained in more detail with reference to FIG. 4.

It should be noted that the number and location of the inlet and/or outlet NOx sensors 214, 314 of the inlet and/or outlet sensor units 208, 302 described herein are merely exemplary. For example, in other embodiments, the inlet and/or outlet sensor units 208, 302 may include any other sensor such as, a Sulfur Oxide (SOx) sensor, a Carbon Monoxide (CO) sensor, a Hydrocarbon (HC) sensor, an Infrared (IR) sensor, a Thermal Imaging (TI) sensor, a temperature sensor, a pressure sensor, and so on as per system design and requirements. Also, the inlet and/or outlet sensor units 208, 302 may be located at any other location on the aftertreatment system 120 and/or the engine system 110 as per system design and requirements. Further, in some embodiments, the system may include any one of the inlet sensor unit 208 and the outlet sensor unit 302. A person of ordinary skill in the art will appreciate that the inlet and outlet sensor units 208, 302 may be similar or different in construction and design, as the case may be.

Referring to FIG. 4, a perspective view of an exemplary embodiment of the active cooling assembly 212 is illustrated. For the purpose of clarity and explanation, the inlet NOx sensor 214 and the inlet sensor circuitry 216 have been omitted from FIG. 4. In the present embodiment, the active cooling assembly 312 is substantially similar in structure and function to the active cooling assembly 212. The active cooling assembly 212 is configured to control a temperature of the inlet sensor unit 208 based, at least in part, on a circulation of a coolant flow therethrough. The coolant may be any coolant known in the art, such as water, a water based coolant, an oil based coolant, an air based coolant, such as ambient air, and so on.

In the present embodiment, the active cooling assembly 212 includes a housing 404. The housing 404 has a hollow configuration. The housing 404 is provided on the body 210 of the inlet sensor unit 208 in a manner such that the inlet sensor unit 208 is provided in conductive thermal contact with and is positioned within the active cooling assembly 212. The housing 404 includes a coolant inlet 406, a coolant outlet 410, and at least one coolant path 408 connected therebetween. The coolant path 408 is provided in conductive thermal contact with at least a portion of one face of the inlet sensor unit 208. For example, in the illustrated embodiment, the coolant path 408 is provided on more than one face of the inlet sensor unit 208. In other embodiments, the coolant path 408 may be provided on any one face of the inlet sensor unit 208.

The coolant inlet 406 is configured to receive the coolant flow into the active cooling assembly 212. The coolant inlet 406 may be provided in fluid communication with the aftercooler 118. More specifically, the coolant inlet 406 may be provided in fluid communication with an inlet section of the aftercooler cooling circuit. The coolant inlet 406 is configured to receive the coolant flow into the active cooling assembly 212 therefrom. The active cooling assembly 212 functions to actively cool the inlet sensor unit 208 via heat transfer from either the environment external to the inlet sensor unit 208 or the environment internal to the inlet sensor unit 208, or both, to the coolant flow within the active cooling assembly 212.

In the embodiment wherein the engine system 110 may include the intercooler, the active cooling assembly 212 may be provided in fluid communication with an intercooler cooling circuit such that coolant flow is received therefrom. In yet other embodiments, the active cooling assembly 212 may be provided in fluid communication with any other cooling system provided on the machine 100, such as, an engine cooling system, a transmission cooling system, a cooling system associated with an electrical system of the machine 100, an operator cabin cooling system, any other Heating, Ventilation and Air Conditioning (HVAC) unit, and so on.

In the present exemplary embodiment, the active cooling assembly 212 includes the coolant path 408 provided in the housing 404. The coolant path 408 is provided in fluid communication with the coolant inlet 406. The coolant path 408 is configured to circulate the coolant flow through the housing 404 and exchange heat with the inlet sensor unit 208. The active cooling assembly 212 is configured such that the coolant path 408 provides sufficient surface area such that the inlet sensor unit 208 is exposed to the coolant flow to produce the desired heat transfer and temperature moderation; one of ordinary skill in the art would appreciate that a variety of patterns or channels may be provided to create the coolant path 408.

One of ordinary skill in the art will appreciate that the coolant may be at a temperature lower than the temperature of the inlet sensor unit 208. In such a situation, the coolant may exchange heat with the inlet sensor unit 208 in order to lower the temperature of the inlet sensor unit 208. In the illustrated figures, the coolant path 408 is provided within the housing 404 in a serpentine configuration. In other embodiments, the coolant path 408 may be provided within the housing 404 in a coiled configuration, a helical configuration, a zigzag configuration, a configuration having a plurality of parallel paths, or in any other manner such that the coolant may flow through the housing 404 of the active cooling assembly 212.

The coolant outlet 410 is provided in fluid communication with the coolant path 408. Further, in the embodiment wherein the coolant is provided from the aftercooler 118, the coolant outlet 410 is provided in fluid communication with an outlet section of the aftercooler cooling circuit. The coolant outlet 410 is configured to exit the coolant flow from the active cooling assembly 212. In other embodiments, the coolant may flow to other parts or components of the engine system 110. In some embodiments, the housing 404 may further include a plurality of fins (not shown) provided thereon. The plurality of fins may be configured to provide heat exchange between the housing 404 and ambient air.

Additionally, the active cooling assembly 212 includes at least one mounting leg 412 extending from the housing 404. The at least one mounting leg 412 may be configured to affix the housing 404 to the aftertreatment system 120, the exhaust conduit and/or the inlet sensor unit 208. Further, the at least one mounting leg 412 may extend in such a manner so as to separate the inlet sensor unit 208 away from a mounting surface of the aftertreatment system 120 or the exhaust conduit, in order to further control, lessen or prevent the increase in the temperature of the inlet sensor unit 208 due to conduction with a relatively heated surface of the aftertreatment system 120 or the exhaust conduit respectively.

In another embodiment, the at least one mounting leg 412 may be provided extending from the body 210 of the inlet sensor unit 208 in order to affix the inlet sensor unit 208 to the casing 204 of the aftertreatment system 120. In another embodiment, the at least one mounting leg 412 may be provided extending from the active cooling assembly 212 in order to affix the active cooling assembly 212 to the casing 204 of the aftertreatment system 120. In yet other embodiments, the body 210 of the outlet sensor unit 302 or the housing 404 of the active cooling assembly 212 may be affixed to the casing 204 of the aftertreatment system 120 by any fastening method known in the art such as, welding, riveting, bolting, and so on.

Components of the active cooling assembly 212 may be made of at least one of a metal and a polymer known in the art. More specifically, the coolant inlet 406, the coolant path 408, and the coolant outlet 410 may be made of any metal or alloy such as steel, copper, and so on, or any known polymer. However, materials with high heat transfer coefficients are especially favorable due to their ability to quickly absorb heat from the respective sensor unit. The coolant path 408 may be made of any metal or alloy such as steel, copper, and so on. Further, the housing 404 may be made of any metal or alloy such as steel, copper, and so on or any known polymer. In one embodiment, the housing 404 may be affixed to the body 210 of the inlet sensor unit 208 by any fastening method known in the art such as, welding, bolting, riveting, and so on.

INDUSTRIAL APPLICABILITY

During operation of the aftertreatment system 120, the temperature of the NOx sensor may increase beyond a threshold temperature limit. As a result, the NOx sensor may provide inaccurate readings, and in some situations may experience failures. The active cooling assembly 212, 312 described herein, allows for controlling the temperature of the inlet and outlet NOx sensor 214, 314 within acceptable limits, thus improving sensor life and overall performance. The active cooling assembly 212, 312 allows for the circulation of the coolant flow therethrough, thereby reducing the temperature of the inlet and outlet sensor unit 208, 302 respectively via heat exchange with the coolant flow. The active cooling assembly 212, 312 utilizes a portion of the coolant from an existing cooling circuit present on the machine, by diverting the portion of the coolant to flow through the active cooling assembly 212, 312. Accordingly, this may cause a reduction in complexity of the system design and may also cut down on an overall cost of otherwise having to include an additional cooling arrangement in the system.

A method 500 of working of the active cooling assembly 212 will now be described. Referring to FIG. 5, a flowchart of the method 500 is illustrated. The method 500 will be explained with reference to the inlet sensor unit 208, but may also be used to explain the working of the outlet sensor unit 302 without any limitation. At step 402, the active cooling assembly 212 is provided in association with the inlet sensor unit 208. The inlet sensor unit 208 includes at least one of the inlet NOx sensor 214 and the inlet sensor circuitry 216.

At step 504, the coolant flow is received into the coolant inlet 406 of the active cooling assembly 212. In one embodiment, the coolant flow is received from the aftercooler cooling circuit. In other embodiments, the coolant flow may be received from any other system such as, the intercooler cooling circuit, the engine cooling system, the transmission cooling system, the cooling system associated with the electrical system of the machine 100, the operator cabin cooling system, any other Heating, Ventilation and Air Conditioning (HVAC) unit, and so on.

At step 506, the coolant flow is circulated though the active cooling assembly 212. More specifically, the coolant flow is circulated through the coolant path 408 provided in the housing 404 of the active cooling assembly 212. At step 508, the temperature of the inlet sensor unit 208 is controlled based, at least in part, by the circulation of the coolant flow therethrough. For example, during operation of the engine system 110, the temperature of the coolant is relatively lower than the temperature of the inlet sensor unit 208. During flow of the coolant through the coolant path 408, the coolant may exchange heat with the inlet sensor unit 208 and provide cooling thereof. Further, the coolant flow is exited from the active cooling assembly 212 and returned to the aftercooler cooling circuit through the coolant outlet 410. In the embodiment when the coolant flow is received into the active cooling assembly 212 from any other cooling circuit or system, the coolant flow is returned to the respective cooling circuit or system. Additionally, conduction of heat from the mounting surface of the aftertreatment system 120 or the exhaust conduit, as the case may be, into the sensor unit may be controlled by using at least one mounting leg 412 on the active cooling assembly 212.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof 

What is claimed is:
 1. An actively cooled nitrous oxide sensor module comprising: a sensor unit comprising at least one nitrous oxide sensor and at least a portion of circuitry associated with the at least one nitrous oxide sensor; and an active cooling assembly thermally coupled to the sensor unit, the active cooling assembly comprising: a coolant inlet; a coolant outlet; and a coolant path disposed between the coolant inlet and the coolant outlet, wherein the active cooling assembly is configured to control a temperature of the sensor unit based, at least in part, on a circulation of a coolant flow therethrough.
 2. The actively cooled nitrous oxide sensor module of claim 1, wherein the active cooling assembly includes a housing having a hollow configuration.
 3. The actively cooled nitrous oxide sensor module of claim 1, wherein the active cooling assembly is provided in conductive thermal contact with the sensor unit.
 4. The actively cooled nitrous oxide sensor module of claim 1, wherein the active cooling assembly is disposed such that the coolant path is in conductive thermal contact with at least a portion of one face of the sensor unit.
 5. The actively cooled nitrous oxide sensor module of claim 1 further comprising one or more mounting legs extending from at least one of the sensor unit and the active cooling assembly, the one or more mounting legs configured to control conduction of heat from a mounting surface to the sensor unit.
 6. The actively cooled nitrous oxide sensor module of claim 1, wherein the coolant path has a serpentine configuration.
 7. The actively cooled nitrous oxide sensor module of claim 1 further comprising: an aftercooler in fluid communication with the active cooling assembly such that at least a portion of the coolant flow is received into the active cooling assembly therefrom.
 8. The actively cooled nitrous oxide sensor module of claim 1, wherein the active cooling assembly is made of at least one of a metal and a polymer.
 9. An engine system comprising: an engine having an exhaust conduit; a reductant injector coupled to the exhaust conduit; a selective catalytic reduction module in fluid communication with the reductant injector, the selective catalytic reduction module positioned downstream of the reductant injector with respect to an exhaust gas flow; and an actively cooled nitrous oxide sensor module comprising: a sensor unit provided in association with the selective catalytic reduction module, the sensor unit comprising at least one nitrous oxide sensor and at least a portion of circuitry associated with the at least one nitrous oxide sensor; and an active cooling assembly thermally coupled to the sensor unit, the active cooling assembly comprising: a coolant inlet; a coolant outlet; and a coolant path disposed between the coolant inlet and the coolant outlet, wherein the active cooling assembly is configured to control a temperature of the sensor unit based, at least in part, on a circulation of a coolant flow therethrough.
 10. The engine system of claim 9, wherein the sensor unit is disposed at an inlet of the selective catalytic reduction module.
 11. The engine system of claim 9, wherein the sensor unit is disposed at an outlet of the selective catalytic reduction module.
 12. The engine system of claim 9, wherein the coolant inlet is in fluid communication with an aftercooler associated with the engine system.
 13. The engine system of claim 9, wherein the coolant outlet is in fluid communication with an aftercooler associated with the engine system.
 14. The engine system of claim 9, wherein the actively cooled nitrous oxide sensor module is mounted on the exhaust conduit.
 15. The engine system of claim 14, wherein the actively cooled nitrous oxide sensor module further includes one or more mounting legs extending from at least one of the sensor unit and the active cooling assembly, the one or more mounting legs configured to control conduction of heat from the exhaust conduit into the sensor unit.
 16. The engine system of claim 9, wherein the active cooling assembly is provided in conductive thermal contact with the sensor unit.
 17. The engine system of claim 9, wherein the active cooling assembly is disposed such that the coolant path is in conductive thermal contact with at least a portion of one face of the sensor unit.
 18. A method for cooling a nitrous oxide sensor, the method comprising: providing an active cooling assembly in association with a sensor unit for the nitrous oxide sensor; receiving a coolant flow into a coolant inlet of the active cooling assembly from an aftercooler; circulating the coolant flow through a coolant path of the active cooling assembly; and controlling a temperature of the sensor unit based, at least in part, on the circulation of the coolant flow therethrough.
 19. The method of claim 18 further comprising: discharging the coolant flow from the active cooling assembly.
 20. The method of claim 18 further comprising: controlling conduction of heat from a mounting surface into the sensor unit by using one or more mounting legs. 